IGF-1 protects against diabetic features in an in vivo model of Huntington's disease

• Published in: Experimental neurology Vol. 231; no. 2; pp. 314 - 319
• Main Authors: Duarte, A.I., Petit, G.H., Ranganathan, S., Li, J.-Y., Oliveira, C.R., Brundin, P., Björkqvist, M., Rego, A.C.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 01-10-2011; Elsevier
• Subjects: Animals; Biological and medical sciences; Blood Glucose - drug effects; Body weight; Body Weight - drug effects; Clinical Medicine; Degenerative and inherited degenerative diseases of the nervous system. Leukodystrophies. Prion diseases; Disease Models, Animal; Glucose Intolerance - drug therapy; Glucose Intolerance - metabolism; Huntington Disease - genetics; Huntington Disease - metabolism; Huntington's disease; Hyperglycemia; IGF-1; Insulin; Insulin - blood; Insulin-Like Growth Factor I - metabolism; Insulin-Like Growth Factor I - pharmacology; Insulin-Like Growth Factor I - therapeutic use; Klinisk medicin; Medical and Health Sciences; Medical sciences; Medicin och hälsovetenskap; Mice; Mice, Transgenic; Motor Activity - drug effects; Neurologi; Neurology; R6/2 mice; BACHD; GH; BDNF; Body weight; CAG; CNS; Htt; IR; IGF-1; Huntington's disease; Insulin; R6/2 mice; Hyperglycemia; OD; HPA; SEM; YAC; polyQ; HD; IGF-1R; NSB; WT; Endocrinopathy; Pancreatic hormone; Nervous system diseases; Diabetes mellitus; Rodentia; Huntington disease; Insulin like growth factor 1; Genetic disease; Cerebral disorder; Vertebrata; Mammalia; Mouse; Animal; Central nervous system disease; Degenerative disease; Models; Extrapyramidal syndrome
• ISSN: 0014-4886; 1090-2430
• DOI: 10.1016/j.expneurol.2011.06.016

Huntington's disease (HD) is the most prevalent polyglutamine expansion disorder. HD is caused by an expansion of CAG triplet in the huntingtin (HTT) gene, associated with striatal and cortical neuronal loss. Central and peripheral metabolic abnormalities and altered insulin-like growth factor-1 (IGF-1) levels have been described in HD. Thus, we hypothesized that restoration of IGF-1-mediated signaling pathways could rescue R6/2 mice from metabolic stress and behavioral changes induced by polyglutamine expansion. We analyzed the
in vivo effect of continuous peripheral IGF-1 administration on diabetic parameters, body weight and motor behavior in the hemizygous R6/2 mouse model of HD. We used 9
week-old and age-matched wild-type mice, subjected to continuously infused recombinant IGF-I or vehicle, for 14
days. IGF-1 treatment prevented the age-related decrease in body weight in R6/2 mice. Although blood glucose levels were higher in R6/2 mice, they did not reach a diabetic state. Even though, IGF-1 ameliorated poor glycemic control in HD mice. This seemed to be associated with a decrease in blood insulin levels in R6/2 mice, which was increased following IGF-1 infusion. Similarly, blood IGF-1 levels decreased during aging in both wild-type and R6/2 mice, being significantly improved upon its continuous infusion. Although no significant differences were found in motor function in R6/2-treated mice, IGF-1 treatment highly improved paw clasping scores. In summary, these results suggest that IGF-1 has a protective role against HD-associated impaired glucose tolerance, by enhancing blood insulin levels.
► IGF-1 prevents age-related decrease in body weight in R6/2 mice. ► IGF-1 decreases glycemia and increases insulin and IGF-1 in R6/2 mice. ► IGF-1 highly improves paw clasping scores in R6/2 mice.